Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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r`~ WI'l'H CLIP-ON l)RAW-IN (-,~IPS FOR A WITHI)RAWABLE MULTIPOLE
CIRCUIq` BI~AK~
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Background of the invention
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The invention relates to a withdrawable multipole circuit
breaker which is able to be moved in translation between two end
of draw-in and extraction travel positions, inside a frame
shaped as a parallelipipedic housing, comprising an opening in
the front panel enabling the cireuit breaXer to be extracted and
a rear wall opposite the circuit breaker passage opening, said
wall being equipped with an insulating support -through whieh
fixed connection terminals pass, each comprising a first part
external to the housing for electrical connection, notably to an
external busbar, and a second part internal to the housing on
which is mo~nted a draw-in grip securedly fixed to the frame-
said grip cooperating in the drawn-in position with a corres-
ponding contact terminal of a pole of the circuit breaker.
Aeeording to a known withdrawable circuit breaker, each draw-in
grip is fixed directly by assembly means to the rear wall of a
low voltage cubicle frame. A three-phase circuit breaker
requires six draw-in grips to be fitted on the frame. The
manufacturing cost of such frames is relatively high, and
inspecting the grips when maintenanee opera-tions are earried out
is complicated, as the rear wall of the frame has to be
partially dismantled.
It has also been proposed to fit the draw-in grips on the
circuit breaker contact terminals by means of a double elip-on
system ensuring bilateral gripping on both the opposite sides of
the contact terminal. A device of this kind is described in U.S.
Patent N 3,427,41g. Fitting and removing this type of grips
nevertheless still remain difficult.
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The object of the invention is to make draw-ln grip fitting and
removal operations easy, and to use a standard frame designed to
: be individualized in the final phase of the assembly operation
by a judicious choice of the draw-:Ln grips and connection
terminals in terms of the circult breaker rating, the type of
terminal connection and the electrodynamic withstand of the
grips.
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Summary of the invention
The frame according to the invention is characterized by the
fact that the end of thel second internal part of each fixed
connection terminal comprises a single latching edge operating
in conjunction with a notch of conjugated shape, arranged in the
draw-in grip, onto which it clips. The grip is removed by
tilting the latter, causing said edge to be automatically
unclipped from the notch.
It can be noted that clipping and unclipping the grip can be
carried out quickly without tools, thus making assembly and
inspection operations easy.
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According to one embodiment of the invention, the latching edge
extends transversely along a large face at the end of the
connection terminal, the smooth opposite parallel face being
shaped as a sliding surface for the contact fingers of the grip,
in such a way that the tilting poin-t of the grip when dis-
assembly takes place coincides appreciably with the position of
the latching edge.
The structure of the draw-in grip is advantageously symmetrical
so as to enable it to be fitted onto the connection terminal
quickly, whichever way the grip is facing.
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Brief description o the drawings
Other advantages and characteristics will become more clearly
apparent from -the following description of different embodiments
of the invention, given as examples only and represented by the
accompanying drawings, in which :
- figure 1 is a partially cutaway perspective view, showing the
rear wall of a frame according to the invention ;
- figure 2 shows an enlarged scale view of the draw-in grip
clipped onto the fixed connection terminal, the circuit breaker
contact terminal being represented in the drawn-in position
(dashed lines), and in the drawn-out position (bold lines) ;
- figure 3 is an elevation view of the fixed connection terminal
according to figure 2 ;
- figure 4 is a plan view of figure 3 ;
- figure 5 represents an enlarged scale elevation view of a
contact finger of the grip according to figure 2.
Description of the preferred embodiment
In the figures, a fixed frame is shaped as a parallelipipedic
housing 12, acting as a support for a withdrawable type
multipole circuit breaker 14, notably with an insulated moulded
casing 16. Each pole of the circuit breaker 14 comprises a pair
of contact terminals 18, protruding from the rear face of the
casing 16 and cooperating in the drawn-in position of the
circuit breaker with a pair of superposed draw-in grips 20,
securedly united to the frame 10. The low voltage, high rating
circuit breaker 14 can be moved in translation in both
directions (arrow F) between two end of draw-in and extraction
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travel positions, by actuation of an auxiliary operating
mechanism (not shown) disposed in proximity to the front panel
of the housing 12.
Each draw-in grip 20 comprises a plurality of pairs of opposing
elementary contact fingers 22, 24, operating in conjunction with
compression springs 26, disposed on either side of the fingers,
the assembly being arranged inside a connection cage 28. Each
elementary contact finger ~2, 24; is shaped as a bridge made of
conducting material, notably copper, extending according to the
longitudinal draw-in direction (arrow F) and comprising two end
contacts ~22 a, 22 b ; 24 a, 24 b) and an external central face
30 disposed between the end contacts to act as a bearing surface
for the corresponding spring 26.
The opposing contact fingers 22, 24 of each pair are elastically
urged towards one another by the compression action of the
springs 26 in the central area, leaving at each end of the grip
20, a gap 32, 34 (figure 2) between the protuberances of the end
contacts 22 a, 24 a ; 22 b, 24 b. The gap 34 allows clip-on
fixing of the grip 20 onto a connection terminal 36 permanently
fixed by the brackets 38, 40 to an insulating support 42 of the
rear wall of the housing 12. The opposing gap 32 is designed for
drawing-in of the corresponding contact terminal 18 of the
circuit breaker 14, when the latter is inserted in the housing
12.
Each rectangular-shaped connection terminal 36 (figures 3 and 4)
is provided with orifices 44 enabling connection to an external
busbar (not shown) extending to the rear of the housing 12. The
connection terminal 36 passes longitudinally through an aperture
46 (figure 2) provided in the insulating support 42, and
comprises in addi-tion holes 48 for fixing the angle-brackets 38,
40. In the mounted position of the connection terminal 36, the
holes 48 are located appreciably in the vertical plane of the
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support 42, and the brackets 38, 40 are fixed by means of screws
S0 onto the external face 52 of the support 42, opposite the
grip 20. The right-hand end 54 (in figure 2) of the connection
terminal 36 is located inside the housing 12, and is provided
with a latching edge 56 extending transversely along the large
upper horizontal face 57 of the terminal 36 (see figures 3 and
4). The latching edge 56 is single and coopera-tes, when the grip
20 is clipped on, with a notch 58 or groove of conjugated shape,
arranged in each upper contact finger 22 in proximity to the end
contact 22 b. The lower horizontal face 60 of the terminal 36 is
smooth and acts as a sliding surface for the lower contact
fingers 24.
In figure 5, each elementary contact finger 22 of the grip 20
presents a symmetrical profile in relation to the vertical mid-
plane perpendicular to the bearing face 30 of the sprinq 26. The
contact finger 22 is fitted with two symmetrical notches 58,
enabling the grip-20 to be clipped onto the terminal 36 by
either one of the opposing gaps 32 or 34.
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The lower contact fingers 24 of the grip 20 may be devoid of
locking notches 58, as represented in figure 2, or on the
contrary present an identical structure to that of figure 5. In
the latter case, the grip 20 is totally symmetrical, both in
relation to the vertical mid-plane and to the horizontal mid-
plane.
~'itting the draw-in grip 20 onto the connection terminal 36 is
performed by clipping the edge 56 into the locking notch 58 of
the contact fingers 22. The grip 20 remains in the clipped-on
position on the connection terminal 36, when extraction movement
of the circuit breaker 14 takes place, during which the contact
terminal 18 is freed from the draw-in grip 32 by translational
pull to the right, the withdrawn position being represented by
the bold lines in figure 2. The latching edge 56 constitutes a
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unidirectional stop in the extraction direction, so as to retain
the grip 20 posltively on the connection terminal 36, despite
the gripping effect exerted by the contact fingers 22, 24 on the
opposing faces of the withdrawable contact terminal 18.
The draw-in grip 20 can be easily disassembled without tools by
a slight tilting of the cage 28, causing the latching edge 56
and the corresponding notch 58 to be unclipped. The tilting
point of the grip 20 coincides appreciably with the position of
the edge 56. The grip 20 is then disunited from the connection
terminal 36 and can be removed easily when inspection of the
circuit breaker condition is carried out.
It can be noted that a standard frame 10 can be used, which can
be individuali~ed when the assembly operation has been completed
by a judicious choice of the draw-in ~rips 20 and connection
terminals 36, in terms of the rating of the circuit breaker 14,
the type of connection and the electrodynamic withs-tand (see
figure 1).
The latching edge 56 may of course be disposed at the end of the
lower face 60 of the connection terminal 36, the upper face 57
being in this case smooth.
